I have bought lots of Apple stuff in the US and had the warranty honoured without question here in the UK.
Have you had this happen with an iPhone?
Apple's computer warranties are international - the only product that I understand is country specific is the iPhone. Having said that, one of the things that always impresses me with Apple is their leniency with the warranties - having said that, I have been at a Genius Bar when someone was told that they weren't covered cos their iPhone was from Italy.